Muffler help 993 engine modified too loud

Fredie · 07-18-2020, 12:15 PM

Hello
I have an 86 coupe with a 993 based modified engine. It has many exotic parts and is lots of fun for about 20 miles of street driving. I am changing the car to be more street use and probably no more track use. Bottom line is without a helmet, it drones and is way too loud.
It has instant-g headers with heat and a magnaflow muffler circa 2007.
Any help greatly appreciated.
Regards,
Steve

rw229 · 07-18-2020, 07:08 PM

Looking at the the pipe layout, maybe look at a 997.2 center muffler. I have no idea how it will fit or sound, but from your pic it looks like it may work with some modifications.

H-viken · 07-19-2020, 06:42 AM

First off, go from 2 out to 1 out, then see if you can find a longer muffler

Sboxin · Sboxin's Garage

It might help to talk to -Levi- This is a Thread he did for his 993 engine conversion build with a particular muffler . . .

81 911 SC -> 95 3.6 vram swap track / hot rod build.- help

Regards,
Roy T

Bravoaloha · 07-19-2020, 02:51 PM

I did a similar setup to Levi after talking to him. Steve from Rennsport also endorses the GT3 muffler setup on 3.6 swapped cars as the best performance option with the least amount of drone. If you want to retain heat you need B&B Heat Exchangers custom fabricated to the muffler. If you want to go nuts you can do what Levi and myself did and have cut-outs installed on the lower "loud" input, or you can just pipe to the upper quiet input and block off the lower.

Piped to just the quiet input the car still sounds great and makes plenty of noise. Opened up on loud it is LOUD and has that infamous GT3 howel in the upper RPM ranges. I'm very happy with my setup.

Let me know if you have any questions.

Fredie · 07-26-2020, 08:26 AM

Thank you for the contributions.
I like the GT3 muffler its a good solution. However, I really do not want to re-work my rear bumper and I like the old school look of the outlets on both corners.
This is a tough one that will require some digging. There seems to be very little information in regards to this type of setup. I have decent headers with heat. And I have had the B&B setup on a 3.2 its too loud and drones pretty bad.
Anyone ever try a Magnaflow 12568?

RarlyL8 · RarlyL8's Garage

I've done a few 997 GT3 systems, they work and sound pretty good. Same goes for our Active Exhaust System for headers. If you don't want GT3 tailpipes you might swap out the MagnaFlow for a DynoMax. The inlet pipes will need to be changed as the flow is not the same.

Bravoaloha · 07-26-2020, 04:17 PM

I actually had a magnaflow on my car for a while before doing the the GT3 exhaust and I liked it. Drone wasn't bad, not quiet but not loud.

https://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/1026702-b-b-magnaflow-muffler-2-2-out.html

FS Thread on it, still have it and would be willing to sell

pampadori · pampadori's Garage

I found that my extending the exit pipes on my setup so that they were beyond the rear bumper helped with drone, noise, as well as some exhaust odor.
Might be worth a try.

You could also cut open the muffler and stuff some stainless brillo pads in it and weld it closed again.

Fredie · 07-30-2020, 03:16 PM

Thanks for the offer Bravoaloha. However, that is close to what I have. I am not really looking to go down an R&D path. The support for this application seems to be a bit lacking.
Hey Brian at Rarely Late. I left you a VM. We spoke earlier. Have any suggestions?
Regards,
Steve

sus911 · sus911's Garage

Why not put the Bischoff HE's back on with an M&K 2in2out muffler?
I have them on my 3.2 but with a 2in1out muffler. Bottom end torque is improved and top end is much better (dyno tested) The only time it is loud is at idle. No drone at all when underway no matter what rpm, pretty quiet really and great heat.